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About oceansky

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    Bowdidge Marine Designs

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  1. Boatbuilding with Paulownia?

    When we were first looking at Paulownia, the first thing we did was had it tested through the Queensland Testing Services for its mechanical properties and also a comparitive test against WRC. Paulownia was far lighter in its density (260kg/m^3 compared the WRC 384kg/m^3) and as far as its mechanical properties were concerned, not that much less than WRC. The reason we had it tested was so that when we design to classification society standards (commercial) we've got the data sheet for the said timber. There are various species of Paulownia, some heavier than others. The species grown here in Australia are typically the lightweight species, yet I have heard that in the states, its the heavier species which is grown. (Hence the little difference in weights) All that aside, as a timber for planking, I much prefer Paulownia. Top Stuff
  2. Boatbuilding with Paulownia?

    Actually it's less. WRC is typically around 380 kg/m^3 whereas Paulownia is 260 kg/m^3. Great material to work with !!
  3. Boatbuilding with Paulownia?

    G'day Ken, As a boat building material, it's great ! We use it a lot in all our strip plank designs Highly recommend it regards Mark
  4. Chinese BS1088?? hmmmm

    Thanks Par, Typical BS1088 ply as you mention above is similiar in price to ours here in Oz. However, when it comes to Lloyds Okoume ply, its way more than what your paying !! 4mm - $83 per sheet 6mm - $126 9mm - $147 12mm - $198 15mm - $220 18mm - $243 25mm - $330 And this doesn't include transport charges
  5. Chinese BS1088?? hmmmm

    Curious Par, How much is a sheet of 6mm Lloyds plywood worth in the States ?
  6. Chinese BS1088?? hmmmm

    I couldn't agree with you more mate. To tell you the truth, after testing it and calculating the bending strength and Modulus of Elasticity of the said ply, I was pretty disappointed actually. Especially when considering the price of the plywood against other plys. But yes... that is a story I don't want to get involved with here
  7. Chinese BS1088?? hmmmm

    I wish I could agree with you Par, but unfortunatly I've already found out through one of our clients and also through our own testing that this doesn't hold. One of our clients who was especially chasing a light weight dinghy, asked if I could recalculate one of our designs using the suppliers figures. Using 460kg/m^3, the boat should have come out to approx 40 kg. So, he rang the supplier and purchased the plywood based on the suppliers figures for weight. After building the boat, I asked him to weigh it and to our surprise it came out to 65 kg. The builder went over every part of the boat, trying to figure out where the extra 25 kg came from. So, I opened up my weights and moments spreadsheet, I recalculated the boat using 600 kg/m^3 plywood density and the spreadsheet result was 64.5 kg boat weight. Having some samples of this Lloyds plywood, I then did a density test and yes, the result was ...600kg/m^3. Further testing resulted in 6mm plywood = 600 kg/m^3 9mm plywood = 540 kg/m^3 Overall, through my own research, testing and use of Lloyds Special Service Craft standard, I could say a lot on this subject, particulary in regards to this "approved" plywood and all it's so called marketing, but I feel that I must leave it all for obvious reasons... unsaid. I couldn't agree with you more mate
  8. epoxy ply

    G'day Chris, I recently conducted comparitive tests of various species of plywood and about to conduct tests on plywood with various types of fibreglass. In regards to the plywood itself test, I was actually surprised with the results, particulary the advertised densitys compared with "real" results. Also, in regards to the bending strength and Modulus of Elasticity (or stiffness), here to was a huge difference between the various species of plywood. I hope over the Xmas break to finalise my testing and maybe publishing the results here, or on our website regards Mark
  9. expanded plans

    G'day Chris, I use plastic corner quad that is sold at the Bunnings Hardware store. Its around 3m in length and sells for around $8 a length.
  10. Chinese BS1088?? hmmmm

    Just curious Scott, how often did they audit.? Here in Oz, the EWA audit the plywood companies every 6 months
  11. Chinese BS1088?? hmmmm

    Funny you should say that Scott. Last week I rang "Engineer Woods Australia" also known as Australian Plywoods Assoc. and asked why Gabbon plywood is not allowed under AS2272 standard for marine plywood. They emailed back with the response" Not sufficiently durable for exterior use and difficult to impregnate with preservatives"
  12. Cruise Craft sinks near Gove

    G'day drednought, talking with the boys from the Sydney game boat club, they HATE those ball valves. They're always giving trouble. Crikey, bet the boat was put together by someone new on the job or ...maybe the transom was laid up on a Monday or Friday
  13. Cruise Craft sinks near Gove

    Funny you shoud mention that Sam, anoteher Cruise Craft (7m) also sank of Townsville 3 weeks ago. http://www.cruisecraft.com.au/showroom/walkarounds/cruisecraft_outsider_685.php
  14. Chinese BS1088?? hmmmm

    "Lloyd's doesn't certify plywood any more, so the BS 1088 standard is a purely voluntary classification now" Par, I've questioned this myself about Lloyds not certifying plywood anymore, but I can't find any mention of this anywhere on the web. Where did you find this? regards Mark
  15. edge tracker 426

    G'day Marcus, Thanks for enquirying about the Edge Tracker. In regards to the vertical height, the distance from the sole to the side deck (vertical height) for Edgetracker 426 is 595mm or 1ft -11.5in. The Edge tacker 487 (16ft) is 2ft 1.25in ( 641mm) The edge tracker 548 (18ft) is 2ft 4in (711mm) To build the edgetracker 426 should take approx 2 weeks to build, however this would not be full time as a lot of your time, your just sitting around waiting for the epoxy to cure before beginning the next stage. As an example, we took 2 weeks to build the Mushulu 14, working on average 3-4 hours per day. Building the edge Tracker is pretty easy (like all our designs) as all the components or parts are given with measurements and they're also nested onto plywood sheets to help save on wastage Hope this helps